$58 divided by 10 to give you 10% which is $5.80. Multiply $5.80 by 2 to find 20%, which is $11.60. So a 20% tip of $58 is $11.60.
Whenever you see a percentage you can think about it as 20÷100. So when you want to find how much is the 20% in a 58$ bill you can multiple 58 with the 20÷100 which is 58*20÷100=11,6
Find 10% first, so divide the total ($58) by 10. So 10% is $5.8...then 20% is double 10%, so multiply the $5.8 by 2, which gives you $11.6
$58 bill with a 20% tip on top - 58/10=5.8 5.8x2=11.6 $11.60 tip.